RFID mutual authentication verification session

Abstract

In a protocol for preserving the privacy of communications between a RFID reader and a RFID tag, two distinct actions are taken. First, the reader and the tag must be mutually authenticated as being authorized participants in the communications. After that process is successfully completed, the authenticity of each authorized participant must be validated prior to each subsequent communication between reader and tag.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to radio frequency identification (RFID) systems, and, more particularly, to methods of and devices for protecting the security of communications between RFID tags and readers.BACKGROUND OF THE INVENTION[0002]In the most basic terms, RFID systems consist of a RFID tag implemented to provide information stored in the tag pertaining to the identity and perhaps features or characteristics of an object to which the tag is affixed, and to communicate that information via an RF signal to a RFID reader in response to an RF interrogation signal received by the tag from the reader. In most instances of current use, a single reader is used to commence individual communication sessions or transactions with a multiplicity of tags.[0003]Typically, objects bearing the tags are moved past the fixed location of the reader, which is remote from the tags but within the communication range, or response range, of each tag as the tag tr...

AI Technical Summary

Benefits of technology

[0018]It is a principal object of the present invention to provide a relatively simple method or protocol for achieving mutual authentication of a RFID tag and an authorized RFID reader in advance of and throughout a communication session between them.

[0021]In the preferred protocol of the invention, the authorized RFID reader sends a command with an encrypted CRC and the RFID tag decrypts the CRC to make certain the encrypted CRC is correct. Similarly, the tag sends a response to the reader's command with an encrypted CRC and the reader decrypts the CRC to make sure this encrypted CRC is also correct. If both are correct, a communication session or transaction is commenced, but continuous verification of mutual authentication is required in order that the transaction be allowed to continue. If each encryption / decryption is not found to be correct; the reader and tag must abort the transaction, and the mutual authentication is required to be repeated from the start. The use of the CRC field, which is in the data stream typically appended to every command and response, allows the state machine to perform as designed. There is no need for special states during the authentication session or any additional time to achieve this.

[0023]Another object of the invention is to provide a method of assuring privacy of communications between an active or a passive RFID tag and a remote authorized RFID reader within communication range of the tag, to prevent access to the tag's stored data by an unauthorized reader, in which the method includes performing mutual authentication of the tag and the authorized reader as a prerequisite to a communication transaction between the two; and thereafter continuously verifying the mutual authentication as a prerequisite to each subsequent communication during the transaction.

[0024]A related object is to provide a protocol for safeguarding the security of RFID communications between a RFID authorized reader and a RFID tag within an RF response range of the reader, so as to provide read protection for at least a portion of the tag's memory against intrusion by an unauthorized reader, including conducting a process of mutually authenticating the tag and the authorized reader as being authorized to participate in a series of transactions involving a readout of data from the read-protected portion of the tag's memory; and separately verifying the authenticity of the reader as having that authority before each transaction in the series.

Problems solved by technology

Accordingly, a passive RFID tag is quite limited with respect to the amount of data that can be furnished in its response to a reader's query, usually consisting of only fixed, invariable information stored in the tag, e.g., an ID number and perhaps a small amount of additional data.

The on-board, or on-chip, battery of an active RFID tag can give the tag a greater response range, along with greater accuracy, reliability and data storage capacity, but the active tag has the aforementioned disadvantages of greater cost and size relative to the passive tag.

The battery itself can be quite small, but not enough to overcome the size disadvantage.

There are concerns, however, over potential loss of privacy and theft of personal identity information as a result of the growing use of RFID tags.

In the Vajda article, the desire to provide security in low-cost RFID tags is viewed as challenging because of the highly resource-constrained nature of the tags, and their inability to support strong cryptography.

However, Vajda presents the complexity of requiring two states or modes of operation of the tags, and the distinct possibility that an unauthorized reader could penetrate a tag's defense against acquisition of its secure data by gaining entry through the more open ID mode notwithstanding its designation as the locked state.

In addition, Vajda's use of a list of pseudonyms has problems in the relatively large number of messages required, as well as the cost factor associated with frequent updating of those pseudonym lists and secret keys, and over-reliance on the premise that an unauthorized reader can only observe a limited number of consecutive runs of the protocol.

Such tracking of tagged library books raises the specter of surveillance of library patrons and their reading habits.

Concern over violations of security and privacy of communications between authorized reader and tag may also be present with a passive tag, but the ability to set up equipment that maintains power at the tag via RF energy at all times is much more difficult, albeit possible.

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